ASON (Automatic Switching Optical Network) has the function of automatic discovery of network control topology and resource topology, on which basis, the automatic rerouting recovery in case of failure and the automatic reestablishment of end-to-end SC (Switched Connection) or SPC LSP (Soft Permanent Connection Label Switch Path) can be implemented.
Wherein the automatic discovery of resource topology is a critical premise, which relates to the discovery of local TE (Traffic Engineering) link and data link, and information flooding. The particular process includes:                1. discovering the local optical interfaces, establishing and maintaining the corresponding control channels;        2. performing link management, such as, connectivity verification of data link and consistency verification of TE link, etc.;        3. notifying other nodes of its information flooding after passing the consistency verification of the TE link;        4. establishing on each node a consistent TE link resource database for path calculation of LSP (Label Switch Path) establishment and rerouting recovery.        
For the distributed ASON, the steps for LSP reestablishment and rerouting recovery are as follows:                1. calculating an LSP on the ingress node according to the obtained information of network resource topology by use of the traffic engineering based path algorithm;        2. allocating timeslot labels, reserving resources, and establishing cross-connection over the network element nodes along the LSP via the signaling protocol, wherein the allocation of timeslot labels is achieved by the local LRM (Link Resource Manager).        
The timeslot statuses between the adjacent network elements should be kept consistent generally, but inconsistency between the adjacent network elements may occur in the following cases:                (1) The user configures the traditional static cross-connection on a single node by the EMS (Element Management Systems) as required, but only configures some timeslots occupying one end of the link and does not configure or reserve timeslots corresponding to the other end. As shown in FIG. 1, in the TE link 110, the EMS 100 configures the timeslot resource of the end A as occupied, while the timeslot of the end B is still configured as idle, which results in the inconsistency of the timeslot statuses on the two ends of the TE link.        (2) During deletion of an LSP, the LSP can not be deleted successfully because of an abnormal resetting of certain network element node, an the like, which results in the case that, the corresponding crossing of some network element nodes, generally upstream nodes, has been deleted, i.e., the timeslot resource of the corresponding TE link has been released, while the corresponding crossing of some other network element nodes, generally downstream nodes, is remained, i.e., the corresponding TE link timeslot resource is still occupied. As a result, the link timeslot statuses between the abnormally reset network element node and its adjacent node may be inconsistent. FIG. 2 shows a LSP 200 which ingress node is node A and egress node is node F, and the LSP 200 passes through the intermediate nodes B, C, D and E. The node D has been reset and restarted, on the nodes A, B and C the corresponding crossings have been deleted and the timeslot resources have been released, while D, E and F remain and the timeslot resources are still occupied. As a result, there is inconsistency of timeslot statuses of the two ends of the TE link 210 between C and D.        
In the above two cases, (1) is an erroneous operation. The inconsistency of link timeslot statuses can be automatically eliminated by setting the other end, i.e. the end B in FIG. 1, as “occupied” by software. While (2) will inevitably occur in the distributed ASON, although the corresponding abnormity processing can be performed by use of the related existing technologies, the timeout of abnormity processing timeout timer is generally set much longer, so that the abnormal situation of the inconsistency of timeslot statuses of the two ends of TE link may last for a long time.
First, the inconsistency of timeslot statuses may cause the unavailability of the corresponding TE link timeslot, and result in the waste of TE link timeslot resources. Secondly, the inconsistency of timeslot statuses can have impact on the establishment of LSP, for example, when certain LSP establishment signaling reaches the network element node on the idle end, a crossing establishment failure will occur, thereby resulting in a failure of the current establishment process. Even if the LSP can be reestablished by means of the Crankback mechanism or other special processing, the total time is prolonged. If the LSP is established for rerouting recovery, the compact will be more severe.
Therefore, the abnormal situation of the inconsistency of TE link timeslot statuses should be detected, avoided and eliminated as early as possible.
At present, the main process of the inconsistency verification of TE link timeslot status in the prior art is as follows: Within the ASON networking, the timeslot status information of TE link of the entire networking is flooded, each node verifies the timeslot statuses of the two ends of each TE link connected with its adjacent nodes periodically by use of this information. If the inconsistency of timeslot statuses on the two ends is discovered, it will be identified specially so as to be avoided when the LSP establishes and allocates timeslot labels. If it is discovered that an originally occupied end becomes idle, the timeslot status of the other end specially identified may be modified as “idle”, so that it can be reused when the LSP is established, thus avoiding the waste of resources.
In the above method, it is required for each node in the networking to flood the timeslot status information of all the TE links of this node. As a result, the amount of communication data is increased significantly. Since there may be the case that flooding refreshment is not in time, multiple continuous verifications are necessary for confirmation in order to avoid false verification, this may cause the detection processing to be not in time, thereby delaying the LSP establishment and rerouting recovery, and resulting in the waste of the TE link timeslot resources.